For me, positioning a DTI (dial test indicator), or dial indicator, on a machine
to carry out some test can be quite difficult, especially so with the milling machine.
In this case, the item being tested will invariably be on the machine table and then
one has the problem of finding some fixed member on which to anchor the indicator.
Even if an anchor point is relatively easy to find, hanging the indicator off this
so that it reaches the workpiece, or work holding device, can be quite difficult.
This is where the central, and simplest feature of this item really makes life easy,
these are the swivel joints and associated bars. Photograph 1 shows an example of
their use in this way. However, the full kit of parts that I have developed, Photograph
2, includes items that expands their use beyond their main purpose, typically, a
magnifier stand, Photograph 3.
These are a major requirement for the system and can be purchased commercially, that
in Photograph 4 (left) being typical, but can be surprisingly expensive, If then
intending to equip the workshop with at least six, making one's own is worth considering.
This especially as they will provide an interesting project for a couple of hours,
they are also more adaptable than the purchased item. The photograph also shows the
shop made item, right.
Most of the half joints will be made to suit the bar diameter, 8mm in my case, but
others may be required to suit other diameters, typically to house the barrel of
a dial indicator, Photograph 5. The joints can easily be dismantled allowing bores
to be mixed and matched to the items being held.
DTI's, as opposed to a dial indicator, are often held using a small dovetail area
on its main body and a special half joint will have to be made to serve this purpose.
However, a small round post is often provided on the indicator as an alternative
mounting arrangement and again a special half joint will be required, this time one
with a smaller bore.